1. Field of the Invention
The present invention relates to safety devices, and in particular to a sharps container for cutting and storing hypodermic needles from syringes and pen needles. The invention also relates to a method for storing the needles and to a process of manufacturing the sharps container.
2. Discussion of the Background
After a hypodermic needle has been used for an injection, it is desirable to remove and store the hypodermic needle in a safe container.
A sharps container which is known in the art comprises an inner box member and an outer housing member. The box and the housing each have an aperture which is dimensioned to receive the hypodermic needle. The box and the housing are hingedly connected to each other so that in an open position the apertures of the box and the housing overlap and the needle may be inserted through both of the apertures to project into the box. After the needle has been inserted into the apertures, the box and the housing are moved with respect to each other, for example in a scissor motion, so that the needle is clipped. After being clipped, the needle drops into the box for storage and subsequent disposal.
The box maybe urged into the open position by spring action, and retained in a closed position by latching the housing with the box. When the container is in the closed position, the apertures of the box and the housing do not overlap, and therefore, the sharps cannot escape the box. However, when the latch is released, the box and the housing move into the open position with respect to each other so that the aperture of the box coincide with aperture of the housing, and therefore, there may exist a situation where a needle is liable to escape from the box through the apertures. An example of such a circumstance is when the openings are positioned such that the force of gravity forces the needle toward the openings and possibly through the openings.
A known solution to the problem of keeping needles from falling out of the box when in the open position is to include a blocking member in the interior of the box. The blocking member includes a ball movable between a blocking position, where the ball blocks the apertures of the box, and an unblocking position, where the ball does not block the aperture of the box. In particular, the ball is movable within the internal housing from the blocking position to the unblocking position, such that the ball is retained in the blocking position. When a needle is inserted into the opening of the box, the ball is forced away from the opening by the action of the inserted needle. After the needle has been broken off and subsequently falls into the box, the ball is returned to the blocking position.
That is, in the known devices, the metal ball was designed to normally block the needle aperture, and to move away from the aperture only when a needle inserted into the aperture moves the ball bearing out of the way. After the needle has been broken off (i.e., clipped and falls into the box), the ball rolls back in front of the needle aperture.
A drawback of such a blocking arrangement is that in many cases the needles do not fall freely into the box after being clipped, but become wedged against the ball, hampering its motion. This renders the device unusable because additional needles cannot be inserted due to the jam.
Another drawback of the known blocking mechanism is that it is not well-suited for short needles because the needles need to be a certain minimum length to push the ball completely out of the way. That is, when a short needle is inserted through both apertures, the ball does not get pushed completely out of the way, and after being clipped, the needle is not allowed to fall into the box, instead becoming wedged against the ball and jamming the aperture of the box.
As described above, the box and the housing are retained in the closed position by latching the box with the housing so that in the closed position the apertures of the box and the housing do not overlap, thereby effectively blocking the opening of the box and preventing the needles from falling out. However, several drawbacks have been observed with known mechanisms for latching the box and the housing. For example, known latch mechanisms include a tab which protrudes from the device and has been known to easily break off, thereby rendering the device unusable.
Another example of known latching mechanisms employs a single tab to retain the box and the housing in a hinged positioned. A drawback of such an arrangement is that the device is prone to inadvertent activation (i.e., inadvertent opening). Yet another drawback of the known latch mechanisms is that the tab is designed to be moved freely whereby the permitted excessive movement of the tab (beyond the range of movement required for unlatching the box and the hosing) facilitates breakage of the tab during the normal operation of the device.